Last night I completed 5/6 of the Da Vinci challenges, missing only the Machines of War challenge. Today I started a new game, played a bit, started another one and noticed that I'd lost all progress on the event, none of the challenges were completed. Then I noticed that I'd also lost my achievements on the Dia De Los Muertos event and I no longer have access to La Catrina?

I restarted the game and "Challenges" was now greyed out in the Events menu. It came back after another restart but the challenges are still missing. I'm connected to Amplifiers. Very annoying, it took me quite a while to get the La Serenissima challenge. 

Okay so disconnecting from Amplifiers and connecting back again seems to have brought back some of the challenge achievements, except that some have now reset to whatever I had in the last game I started today. But La Serenissima is back at least...Still missing La Catrina because some of those challenges reset. 

I have a similar problem: after the latest update I lost progress in all three challenges. This is quite annoying. Fortunately, the tasks which were the hardest stayed intact (e.g. the Mogul one). Seems like a bug to me.

Exactly the same problem here... up!

Same issue as well.

Not able to get the challenges back after disconnecting/reconnecting several times though...

Hope somebody will answer, that's very frustrating

Same thing is happening to me. 

Losing progress, progress not tracking at all and cannot connect to the challenges tab half the time. 

me too 

Likewise for me: I completed a few of the Da Vinci challenges last night, and now I've not only lost that progress but, after restarting Humankind, I can't even access the "Challenges" screen, despite being connected; disconnecting and reconnecting fixes nothing